IP Library › Granted Patent US 9,726,425
Granted Patent B2
US 9,726,425 · App. 12/296,587 · Granted Aug 8, 2017

Method and apparatus for liquefying a natural gas stream

View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 9,726,425
App. No.
12/296,587
Granted
Aug 8, 2017
Kind
B2
Abstract

The present invention relates to a method of liquefying a hydrocarbon stream such as a natural gas stream, the method at least comprising the steps of: supplying a partly condensed hydrocarbon feed stream ( 10 ) to a first gas/liquid separator ( 2 ); separating the feed stream ( 10 ) in the first gas/liquid separator ( 2 ) into a gaseous stream ( 20 ) and a liquid stream ( 30 ); expanding the gaseous stream ( 20 ) thereby obtaining an expanded stream ( 40 ) and feeding it ( 40 ) into a second gas/liquid separator ( 3 ); feeding the liquid stream ( 30 ) into the second gas/liquid separator ( 3 ); removing from the bottom of the second gas/liquid separator a liquid stream ( 60 ) and feeding it into a fractionation column ( 5 ); removing from the top of the second gas/liquid separator ( 3 ) a gaseous stream ( 50 ) and passing it to a compressor ( 6 ) thereby obtaining a compressed stream ( 70 ); cooling the compressed stream ( 70 ) thereby obtaining a cooled compressed stream ( 80 ); heat exchanging the cooled compressed stream ( 80 ) against a stream being downstream of the first gas/liquid separator ( 2 ) and upstream of the fractionation column ( 5 ).

Claims (23)

1. A method of liquefying a hydrocarbon stream, the method at least comprising the steps of:

(a) supplying a partly condensed hydrocarbon feed stream to a first gas/liquid separator;

(b) separating the feed stream in the first gas/liquid separator into a gaseous stream and a liquid stream;

(c) expanding the gaseous stream obtained in step (b) thereby obtaining an expanded stream and feeding said expanded stream into a second gas/liquid separator at a first feeding point;

(d) feeding the liquid stream obtained in step (b) into the second gas/liquid separator at a second feeding point;

(e) removing from the bottom of the second gas/liquid separator a liquid stream and feeding said liquid stream into a fractionation column;

(f) removing from the top of the second gas/liquid separator a gaseous stream and passing the gaseous stream to a compressor thereby obtaining a compressed stream having a pressure above 50 bar;

(g) cooling the compressed stream obtained in step (f) thereby obtaining a cooled compressed stream;

(h) further cooling the cooled compressed stream by heat exchanging the cooled compressed stream obtained in step (g) against a stream being downstream of the first gas/liquid separator and upstream of the fractionation column; and

(i) liquefying the cooled compressed stream, after heat exchanging in step (h), thereby obtaining a liquefied stream.

2. The method according to claim 1 , wherein in step (h) the cooled compressed stream is heat exchanged against the liquid stream removed in step (e) from the second gas/liquid separator.

3. The method according to claim 1 , wherein in step (h) the cooled compressed stream is heat exchanged against at least a part of the expanded stream obtained in step (c).

4. The method according to claim 1 , wherein from the top of the fractionation column a gaseous stream is removed that is heat exchanged against at least a part of the liquid stream from the second gas/liquid separator.

5. The method according to claim 1 , wherein the gaseous stream removed in step (f) from the top of the second gas/liquid separator is heat exchanged against the feed stream, before the gaseous stream is fed to the compressor.

6. The method according to claim 5 , wherein the gaseous stream removed from the fractionation column, after heat exchanging against at least a part of the liquid stream from the second gas/liquid separator, is heat exchanged against the gaseous stream removed from the second gas/liquid separator.

7. The method according to claim 1 , wherein the hydrocarbon stream is a natural gas stream.

8. The method according to claim 1 , wherein the heat exchanging in step (h) is directly heat exchanging.

9. The method according to claim 2 , wherein in step (h) the cooled compressed stream is heat exchanged against at least a part of the expanded stream obtained in step (c).

10. The method according to claim 2 , wherein from the top of the fractionation column a gaseous stream is removed that is heat exchanged against at least a part of the liquid stream from the second gas/liquid separator.

11. The method according to claim 3 , wherein from the top of the fractionation column a gaseous stream is removed that is heat exchanged against at least a part of the bottom stream from the second gas/liquid separator.

12. The method according to claim 2 , wherein the gaseous stream removed in step (f) from the top of the second gas/liquid separator is heat exchanged against the feed stream, before said gaseous stream is fed to the compressor.

13. The method according to claim 3 , wherein the gaseous stream removed in step (f) from the top of the second gas/liquid separator is heat exchanged against the feed stream, before it is fed to the compressor.

14. The method according to claim 4 , wherein the gaseous stream removed from the fractionation column, after heat exchanging against at least a part of the liquid stream from the second gas/liquid separator, is heat exchanged against the gaseous stream removed from the second gas/liquid separator.

Assignments (1)
CHANGE OF NAME Recorded Mar 7, 2022
From: SHELL OIL COMPANY
To: SHELL USA, INC.
Reel/Frame 059694/0819 →